With the development of the construction of Beidou (BD) satellite navigation system network, the BD navigation satellite system provided formal regional service since 2012. The BD navigation satellite system can be compatible with the GPS (global position system) of the US, the GLONASS (Global Navigation Satellite System) of Russia, the Galileo System of European Union, and other satellite navigation systems in the world, and can provide highly precise, reliable positioning, navigating, timing service for various users all-weather, all day around, and all around the world.
However, most of the baseband portion of the receivers with satellite navigation can only receive and process one of or the combination of several frequency-point signals of the B1 of the BD-2, the 1 of the GPS, and the 1 of the GONASS. Seldom can they receive or process eight frequency points of the satellite signals, i.e. GPS 1/2/5, GLONASS 1/2 and BD B1C/B2C/B3C simultaneously. As a result the number of available frequency points is low. For the occasion of original observation type like differential positioning etc. which needs more frequency points, the differential solution requires at least the original observation of two or more frequency point types of signals. Obviously, in this case, the old method can not adapt to the current development.
The present method of processing the eight-frequency-point satellite signal is complicated in structure, which uses a lot of input interfaces, amplifiers, local oscillator circuits, and frequency mixer circuits. Using a large number of circuits remarkably enlarges the size of the PCB, which is disadvantageous for minimizing the satellite positioning receiver, and increases the power consumption of the satellite receiver, at the same time, increases the cost of the hardware. Accordingly, it is difficult to realize receiving the eight-frequency-point satellite signal.